ABSTRACT

Probiotics like S. cerevisiae and micronutrients are intestinal modulator immune booster and growth enhancer. Methionine is lacking in most plant ingredients and availability improves growth. Consequently, six experimental diets varying in inclusion of S. cerevisiae and methionine were produced using mixture methodology principle. F7 was the commercial diet. The inclusion ratio of S. cerevisiae: methionine were as follows Feed 1(F1) 25:0, Feed 2(F2), 5:25, Feed 3(F3), 10:15, Feed 4(F4), 15:10, Feed 5(5), 25:5, and Feed 6(6), 0:25. Diets were made to be corresponding in compositions as follows: F1 to F6, F2 to F5 and F3 to F4. The diets were fed to hybrid of African catfish (Clarias gariepinus) (Female) X Heterobranchus longilis (Male). There are tanks of 20 liters capacities per treatment feed. The hybrids were stocked at 20 fish per aquaria of dimension length weight and height. The fish were feed for a period of 86 days. The best SGR was produced by hybrid fed with feed 5, 6.00±0.42% day'. There was however no significant difference (P>0.05) between the specific growth rate (SGR) of F5 and F1 (P>0.05). Nevertheless the SGR of hybrid fed with F1 was significantly different (P<0.05) that of hybrid fed with corresponding diet F6 (P<0.05). The SGR of hybrid fed with F2 was 3.50±0.37% day'1while the specific growth rate of the corresponding diet F5 was 6.00±0.42% day1the catfish fed with F3 had SGR of 5.44±0.33% day' while those fed with the corresponding diet feed 4 had SGR of 5.70±0.03% day'. The food conversion ratio (FCR) of the catfish was best and similar for hybrid fed with feed F4 and F5 (P>0.05). There high weight gain for catfish fed with F5 followed by those fed with F 1. Based on results substitution of S. cerevisiae with methionine was very beneficial in enhancing growth and survival of hybrid African catfish. Moreover, the substitution enhanced fast growth of fish at fishmeal inclusion as low as 20%.